In recent years, the sophistication and capability of computers has steadily increased. As they have, the number of uses of computers for both business and recreation has increased as well. For example, computer-based virtual reality devices that provide feedback based upon the identification of a user or the detection of a user's physical movements have grown in popularity. These devices (generally referred to hereafter as interactive activity devices for convenience) include, for example, computer games. With these games, a user moves his or her own arms, legs, head or entire body location in order to accomplish the goals of the computer game. Interactive activity devices also include electronic training devices, which are used to improve desired skills for a wide variety of athletic activities or job tasks. For example, with some types of interactive electronic training devices, a user may practice a particular movement of a body part and receive feedback in response, to indicate whether the user is moving in the desired manner.
While a number of different interactive activity devices are growing in use, the tools employed by a user to control these devices are often primitive. For example, many interactive activity devices require that a user wear an unwieldy and sometimes uncomfortable accessory that will allow the device to track the position of the user. These accessories may be, for example, a belt or bands with a prominent reflective disk in front for reflecting infrared waves.
In addition to tracking a user's movement, many computers now are being employed to recognize images. That is, computers now are being used to identify an image and then associate particular information with that image. For example, optical character recognition software can distinguish the letter “T” from the letter “q.” Based upon this recognition, another software program, such as a word processing program, can employ an ASCII value for the recognized character “T.” Still other uses of image recognition include retina pattern and fingerprint scans for personal identification, obstacle and boundary recognition for automobile guidance, and document watermark recognition for navigating a browser to an Internet site associated with the watermark. While techniques for pattern recognition have become very sophisticated, however, pattern recognition is not typically employed in such day-to-day activities as electronic gaming, athletics, or shopping.